Effect of temperature and pressure:
The conductivity of all electrolytes increases with increasing temperature. The variation of molar conductivity at infinite dilution with temperature is given by an empirical equation.
Λ ∞ (t) = Λ ∞ (25) [1+ x (t - 25)]
where Λ∞ (t) and Λ∞ (25) are the value of molar conductivities at t and 25oC respectively, and x is a constant for each electrolyte. For salts x is about 0.022 to 0.025 and for acids and bases it is usually 0.016 to 0.019. It means that molar conductivity increases approximately by 2 percent for every one degree rise in temperature. For strong electrolytes, yet at appreciable concentration, Eq. (4.15) contains well, whereas in case of weak electrolytes, the variation of Λ with temperature is not so regular. The rise in conductance with temperature is due to the decrease in the viscosity of the solution, rise within the speed of the ions and an increase in the degree of ionization in cases of weak electrolytes.
The conductivity increases slightly with increase in pressure. The effect is mainly through changes in the viscosity of the medium, which decrease by an increase in pressure. As a result, the equivalent conductance of the solution will increase with rise in pressure.